| //===--- RCIdentityAnalysis.h -----------------------------------*- C++ -*-===// |
| // |
| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors |
| // Licensed under Apache License v2.0 with Runtime Library Exception |
| // |
| // See http://swift.org/LICENSE.txt for license information |
| // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This is an analysis that determines the ref count identity (i.e. gc root) of |
| // a pointer. Any values with the same ref count identity are able to be |
| // retained and released interchangeably. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef SWIFT_SILOPTIMIZER_ANALYSIS_RCIDENTITYANALYSIS_H |
| #define SWIFT_SILOPTIMIZER_ANALYSIS_RCIDENTITYANALYSIS_H |
| |
| #include "swift/SIL/SILValue.h" |
| #include "swift/SIL/SILArgument.h" |
| #include "swift/SILOptimizer/Analysis/Analysis.h" |
| #include "swift/SILOptimizer/Analysis/DominanceAnalysis.h" |
| #include "swift/SILOptimizer/PassManager/PassManager.h" |
| |
| namespace swift { |
| |
| class DominanceAnalysis; |
| |
| /// This class is a simple wrapper around an identity cache. |
| class RCIdentityFunctionInfo { |
| llvm::DenseSet<SILArgument *> VisitedArgs; |
| DominanceAnalysis *DA; |
| |
| /// This number is arbitrary and conservative. At some point if compile time |
| /// is not an issue, this value should be made more aggressive (i.e. greater). |
| enum { MaxRecursionDepth = 16 }; |
| |
| public: |
| RCIdentityFunctionInfo(DominanceAnalysis *D) : VisitedArgs(), |
| DA(D) {} |
| |
| SILValue getRCIdentityRoot(SILValue V); |
| |
| /// Return all recursive users of V, looking through users which propagate |
| /// RCIdentity. *NOTE* This ignores obvious ARC escapes where the a potential |
| /// user of the RC is not managed by ARC. For instance |
| /// unchecked_trivial_bit_cast. |
| void getRCUsers(SILValue V, llvm::SmallVectorImpl<SILInstruction *> &Users); |
| |
| private: |
| SILValue getRCIdentityRootInner(SILValue V, unsigned RecursionDepth); |
| SILValue stripRCIdentityPreservingOps(SILValue V, unsigned RecursionDepth); |
| SILValue stripRCIdentityPreservingArgs(SILValue V, unsigned RecursionDepth); |
| SILValue stripOneRCIdentityIncomingValue(SILArgument *Arg, SILValue V); |
| bool findDominatingNonPayloadedEdge(SILBasicBlock *IncomingEdgeBB, |
| SILValue RCIdentity); |
| }; |
| |
| class RCIdentityAnalysis : public FunctionAnalysisBase<RCIdentityFunctionInfo> { |
| DominanceAnalysis *DA; |
| |
| public: |
| RCIdentityAnalysis(SILModule *) |
| : FunctionAnalysisBase<RCIdentityFunctionInfo>(AnalysisKind::RCIdentity), |
| DA(nullptr) {} |
| |
| RCIdentityAnalysis(const RCIdentityAnalysis &) = delete; |
| RCIdentityAnalysis &operator=(const RCIdentityAnalysis &) = delete; |
| |
| static bool classof(const SILAnalysis *S) { |
| return S->getKind() == AnalysisKind::RCIdentity; |
| } |
| |
| virtual void initialize(SILPassManager *PM) override; |
| |
| virtual RCIdentityFunctionInfo *newFunctionAnalysis(SILFunction *F) override { |
| return new RCIdentityFunctionInfo(DA); |
| } |
| |
| virtual bool shouldInvalidate(SILAnalysis::InvalidationKind K) override { |
| return true; |
| } |
| |
| }; |
| |
| } // end swift namespace |
| |
| #endif |